In the study of Media Independent Handover (MIH), there are challenges regarding whether or not new procedures are required to trigger the generation of handover events from lower layers (i.e., MAC and PHY layers) as a means to initiate a handover process. Triggers are required in order to determine whether a handover should be executed. An example of a trigger could be the fact that the signal quality of a particular link layer connection has reached a preconfigured threshold indicating that the client station is approaching the fringe of a cell. There has been reluctance to introduce new trigger procedures. Existing handover processes are proprietary and rely on polling mechanisms to retrieve information from the lower layers and to make decisions.
There are no procedures or functionality to generate triggers to the upper layers that are based on state changes, which are characterized as values that cross thresholds previously set by a higher layer entity. In this case, the higher layer entity is the MIH function. Therefore, a method capable of generating these triggers is required.